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Home , Aiptasia mutabilis, Balaclava Bay, Old Harry Rocks, Periclimenes sagittifer

Dorset Seasearch- Summary 2007

Dives- despite the unfavourable weather that . Overall this is a huge increase from last we had last year all of the four Dorset Wildlife year so many thanks to the dozens of Trust Seasearch weekends went ahead and Seasearchers who contributed to this number. we enjoyed great conditions. Our first weekend Our thanks to skippers Mike Markey and Paul was the Seasearch Dive In on the 9/10th June Pike and to Lin Baldock for organising the from Quay. Areas mainly surveyed were Seasearch Dive In weekend in June and Poole Bay. Several of the dives attempted to survey points selected from a DWT Seasearch weekends- The three map of remotely sensed data in order to assist weekends in July, August and September saw in the interpretation of these maps of the several new locations being dived that had seabed. This work was continued in the been selected from the maps of the seabed following three weekends, two from Poole produced though side scan imaging. The aim again (7/8th July and 4/5th August) and one was to continue the Trust’s efforts to ground from Weymouth (15/16th September). Turn out truth the sites in order to assist the was excellent for the Poole dives. Dive boats interpretation of the remotely sensed images. were chartered by DWT leaving the cost per Many of the dives were a great success in person fixed regardless of unfilled places. terms of interesting habitats for the divers to observe and photograph. A few were not so Courses- We had one Observer course which exciting in terms of scenery but none the less was run by Nick Reed in April at provided valuable data on the sites. Another Reserve. Ten divers completed the course and success was the use of the Trusts new subsequently many forms have been returned compact underwater digital cameras by to Dorset by some of those divers, including volunteers. The cameras are very user friendly Jayne and Peter Szekely and Wendy Rooke. and some fantastic results were produc ed (see below). The photos assist in species ID and Recording- For 2007, 110 forms in total were provide an excellent snapshot of the biotopes sent in. Of these forms 70 were Observer present. In September we had fewer divers records and 40 were Surveyor. For some dive present so we took advantage of the space to sites, the records were compiled when divers use the Trust’s remote video camera. Using the were surveying small areas adjacent to each other using a shot line. After this compilation there was a total of 76 survey events for

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DWT Seasearch weekend, June. Photo: K Dawson Divetime . Photo:, P. Tinsley Tompot Blenny. Photo: Ray Drabble

Hermit crab. Photo: Ray Drabble

Sand Mason worms. Photo: Darren Murray cameras over habitats that were difficult to stated, we had 76 separate survey events for interpret from the side scan maps gave us the whole area, with the highest number additional spot check data without having to coming from Swanage Bay (35). The popularity diving them, as well as making extra use of the of this area was due in part to its use by the time between dives. Trust for the organised Seasearch weekends.

Area summaries- The Seasearch recording The table bellow provides a summary of the for Dorset is divided up into five areas biodiversity recorded in Dorset in 2007, spanning from to Poole Bay. followed by a map delivering a short summary Throughout the whole area, 96 habitats and for each of the areas . 325 species and groups were recorded. As

Summary of biodiversity from Dorset Seasearch records

Number of species seen Phylum Common Name of phylum/groups within Phylum Algae Seaweeds- red, green ad brown 50 Annelida Segmented Worms 15 Bryozoa Sea mats 16 Corals, Hydroids, Jellyfish, 42 Crustacea Crabs, lobsters, barnacles 27 Echinodermata Starfish, sea cucumbers, brittlestars 10 Mammalia Mammals 1 Mollusca Snails, limpets, sea slugs, bivalves, cuttlefish, squid 41 Phoronida Horseshoe worms 1 Pisces Fish- bony and cartilaginous 47 Platyhelminthes Flat worms 2 Porifera Sponges 39 Tunicata Sea squirts 34 Total 325

2 Kimmeridge Marine Reserve Area (Mupe Rocks to St Aldhem’s Head) Poole Bay (from Old Harry’s rocks to Eastern edge of Poole Bay) Surveys between: 50° 33.9"N 2° 3.53"W - 50° 36.684"N 2° 12.76"W Surveys between: 50° 40.068"N 1° 53.592"W - 50° 39.416"N 1° 50.46"W

There were sixteen records from the area with 131 species and groups in total recorded. Five records were submitted for the area, with four of these from DWT Seasearch Several of these records were from due to its ideal location for Observer weekends with Mike Markey. Most of these were again to ground truth some training. Subsequently a detailed picture of the Brittle Star beds was built up along with the points selected from remotely sensed data but we also took the opportunity in mixed seaweed habitats of the ledges in the bay. The wreck of the Black Hawk also remains July to survey a fishing ground where there had been reports of seahorses. The popular. Gravel Sea Cucumber (Neopentadactyla mixta) were found in abundance near the conditions were only suitable for a drift dive, which unfortunately did not allow for wreck of the Patricia II. thorough searching and so our seahorse hunt did not return any sightings.

Some of the other more common species in the area included Striped/white Dead man’s fingers Alcyonium( digitatum) were recorded on four of the five (Actinothoe sphyrodeta), (Anemonia viridis), Cuckoo Wrasse (Labrus dives, ranging from rare to occasional. Other frequently seen species included mixtus), Dead man’s fingers (Alcyonium digitatum ) and Potato Crisp Bryozoan (Pentapora Antenna Hydroid (Nemertesia antennina), barnacles (Cirripedia) and Hornwrack foliacea). Rarer species included red sea squirt (Ascidia mentula), Black Tar sponge (Flustra foliacea). Rarer species included Elephants Ear Sponge (Pachymatisma (Dercitus bucklandi) and a Violet Seaslug (Flabellina pedata) johnstonia), Bloody Henry Starfish (Henricia oculata) and Dark tentacled sediment cucumber (Thyone fusus ).

Lyme Bay ( to Lyme Bay) Durlston Marine Research Area Surveys between: 50° 34.65"N 2° (from St Aldhelms Head to Old 28.53"W - 50° 33.48"N 2° 26.854"W Harry’s Rocks) Surveys between: 50° 35.207"N Six records were submitted for the area 2° 1.199"W - 50° 30.294"N 1° off , producing a list of 90 50.187"W different species and groups. T here was a total of 35 records for the area with 251 species and The area is a popular shore diving site groups .observed. with several habitats recorded within a short distance of the beach, including Three of the organised DWT Seasearch dives surveyed in this area, diving sites just off from Swanage. These weekends sediment with life apparent and frequent th short turf on the boulders included the Seasearch Dive In on the 9/10 June. Again we were aiming to ground truth some locations that were difficult to assign occurring there. Greater pipefish and by eye from the maps. The turn out for both the Dive In and the cuttlefish were recorded near to the Portland Bill to Mupe Rocks other two weekends was high and 21 of the records from this area beach. Sites dived further to the West Surveys between: 50° 34.025"N 2° 25.588"W - 50° 35.78"N 2° were from these DWT events. Our thanks to Lin who organised included the Wreck of the Royal 14.13"W the Dive In, and also to Mike Markey our skipper. Adelaide, where one pipefish was seen. Within this area 117 species and groups from 14 dives were On 22nd September, a very rare sighting was made in this area by Some of the most frequently seen recorded. Of these records six were from four dives organised by Matthew Doggett and Polly Whyte at Swanage Pier- a species in the area were the Tompot DWT with Paul Pike on the 15/16th September. From maps sagittifer, the Partner or Snakelocks Anemone blenny (Parablennius gattorugine), produced through remote sensing of the sea bed, we chose Shrimp. The species, which lives in symbiosis with the Snakelocks Double crowned fan worm (Bispira several locations to dive on where the habitat was difficult to Anemone, is more common in the Channel Islands and the volutacornis), Velvet swimming crab determine. The aim was to use the Seasearch data to ground Mediterranean and this is believed to be the first confirmed UK (Necora puber), Star seasquirt (Botryllus truth the maps and to dive areas that usually would not be sighting (see below for photo). schlosseri), Snakelocks anemone chosen for surveys. Our thanks to Paul Pike for his help and skill (Anemonia viridis) and Pollack Those species occurring on the highest number of records in locating our sites which were located off Grove Point and included Double crowned fan worm (Bispira volutacornis) in 27 (Pollachius pollachius). All were seen on and off Osmington and Grove Point on the four of these six dives, ranging in records with an abundance ranging from rare to abundant. second day. Hornwrack (Flustra foliacea) was seen on 25 records, ranging abundance from rare to occasional, and rare to common for the Snakelocks from rare to abundant. Elephant’s ear sponge was also frequently Additionally, a few records surveyed sections of the harbour wall seen (24 records) ranging, also ranging from rare to abundant. Anemone and the Pollack. near . Lots of litter was observed as well as Other species recorded on a high number of dives included abundant fish life, short animal turf and large oysters (Ostrea Orange Crater Sponge (Hemimycale columella), Striped/white3 or edulis) encrusted to the wall. Sandalled anemone (Actinothoe sphyrodeta) and Painted top Map courtesy of Google Earth, 2008 shell (Calliostoma zizyphinum )

Interesting sightings- The nationally scarce Google Earth- All of the locations for the and protected species, the Pink Sea Fan records from previous years Seasearches can (Eunicella verrucosa) was recorded on four now be downloaded to view on Google Earth. separate occasions, ranging from rare to Also available to view on this programme are common in abundance. Interestingly, its most photos of species and habitats from some of easterly recording was Mark’s Reef in Poole the 2007 records. Bay, noted during a DWT weekend. Other http://dorsetwildlife.co.uk/cms/content/view/246/9/ nationally rare species to be recorded were Carpet Coral (Hoplangia durotrix) and Southern The information available on Google Earth will Cup Coral (Caryophyllia inornata) , both with be updated throughout the next season. It can one sighting. The nationally scarce species be a very useful tool in planning future Trumpet Anemone ( mutabilis) (7 Seasearch dives for local divers and those recordings, rare to common in abundance) was from further a field wanting to know more about seen as were Yellow Prong sponge (Adreus the area. fascicularis) and White star or Cluster Anemone (Parazoanthus anguicomus) (also an Many divers took part in the 2007 surveys- our indicator of climate change) both recorded thanks to all of them as well as the skippers, once in Dorset. the photographers who submitted their photos for the database and the dive club members One of the most interesting sightings was the who promoted Seasearch within their Partner or Snakelocks Anemone Shrimp, organisations. Seasearch is a volunteers’ , at Swanage Pier in underwater survey project for recreational September. Show here is the photo taken by divers to actively contribute to the conservation Matthew Doggett of the shrimp in an anemone. of the marine environment. It is coordinated nationally by a Steering Group led by the Marine Conservation Society For details of Seasearch visit www.seasearch.org.uk Seasearch in Dorset is coordinated by Dorset Wildlife Trust. The programme is supported by the JNCC, the Environment Agency and Natural and we gratefully acknowledge their funding. For more details on Dorset Wildlife Trust’s Seasearch programme please visit www.dorsetwildlife.co.uk This report was prepared by K Dawson. All enquiries to [email protected]

Periclimenes sagittifer: Photo: Matt Doggett

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